docs: def satellites_used(feed):
      """Counts number of satellites used in calculation from total visible satellites
      Arguments:
          feed feed=data_stream.TPV['satellites']
      Returns:
          total_satellites(int):
          used_satellites (int):
      """
      total_satellites = 0
      used_satellites = 0
  
      if not isinstance(feed, list):
          return 0, 0
  
      for satellites in feed:
          total_satellites += 1
          if satellites['used'] is True:
              used_satellites += 1
      return total_satellites, used_satellites